Vag-com / VCDS

[ld50]

bit of a random question this one… I’m trying to help a mate with a problem he’s got with his diagnostic software. He’s using Ross-tech Vag-com (now known as “VCDS”) which works great except that the reading from the mass-flow sensor tops out at 364.1 grams/sec and the engine has blatantly got bags more to offer.

Apparently it IS possible to adjust the scaling/limits to allow higher values and I’m digging thru the file structure at the moment to try and find where the limit is imposed but I wonder if anyone else has had experience with the software or this problem?

Emailing the software manufacturers isn’t likely to help since apprently the bloke who wrote it has left so they’re about as clueless as everyone else…and the one bloke who definitely does know how to do it isn’t telling.

ideas anyone?

[no such user]

not played with it much

[Chris S]

Ask Pascal!

[pvl]

I think we need some enginespecs. Then i can correctly interpret things.
Please provide : brand, year, engine-code, modifications to it.

My friend tunes for JD, and has some knowledge of these items… as he also has vag-com. So i can ask him or via him what this problem is abouth. He said that all sport-airfilter that are pre-oiled give lots of problems with the MAF’s. the oil vapourises when there is moist in the air (especially when it’s raining) and the oil is creating a film on the hotwire, and the hotwire burns and gives less readout than in good condition. Perhaps thats the problem …

Greetings,

Pascal

[ld50]

hi pascal, I was hoping you’d have an idea,

this looks like a software problem, I’ll check whether it’s got an oiled filter, but surely a deflection like that wouldn’t be so consistent?

the vag-com readout just stopped abruptly at 364.1gram/sec but the car was still boosting.

There are a few config files which we pretty much went through but there ar also a shedload of “label” files, many of which seem to be made up of other, previous label files as well as additional (new) settings.

So as far as I understand it basically when there is an engine revision or something they just make a new label file which inherits all the properties of the previous one.

If it’s possible to change as we’d like to think, I suspect the key is in understanding that structure and knowing which files to fiddle with.

From a programming point of view it would seem to be a sensible way to write the software – why would you hard-code values into software intended for use on many vehicles.

364.1 also isn’t a “natural” limit number like 255 or 65535 either by the look of it…

I have some ideas for how to figure out which files but if somebody already knows the software it could save a lot of time

As to the engine specs I don’t really know, will check tho, it’s very, very fast though.

Cheers for the input!

[1.8TsyncroB3]

I’ve been using VagCom (VCDS) and following their Yahoo Support group for quite some time. My understanding is that your problem is more likely an ECU software limitation rather than VagCom. Of the varying VAG vehicles I’ve tinkered with, I’ve seen MAF readings much higher than what your getting, so I doubt that it is a VCDS issue.

Another item needing clarification is that the VCDS label files are just that – Label files to direct VCDS to the correct channels for data aquisition, and then LABEL them correctly in accordance with each ECU type being accessed. The label files shouldn’t impose any limitations on the VCDS reading abilities.

A while back I also followed the 1.8T tuning Forums on VWVortex and noticed that there is a huge difference in the readings obtainable when comparing a stock engine to a heavily modified one. The ECU software apparently plays a big part in this.

Now, Getting on to your specific issue of the reading topping out at the same value each time. I would first suspect a faulty MAF, so you need to exchange it with another MAF to confirm that. I’ve seen several MAFs that reacted in a similar fashion, and a replacement gained an improvement.

Regarding the VCDS Software, Uwe is tight on his litle secrets, I doubt that you’ll find much help from them regarding tweeking their tool. You might just ask for help first on the Yahoo group to see what others have experienced regarding the topped out MAF reading. ask the question as if you are software iliterate.

[ld50]

cheers les – I’ll let you know how we get on

[Author]

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